Structural gene variants in the porcine mannose-binding lectin 1 (MBL1) gene are associated with low serum MBL-A concentrations

Mannose-binding lectin (MBL) is a collagenous lectin that kills a wide range of pathogenic microbes through complement activation. The MBL1 and MBL2 genes encode MBL-A and MBL-C, respectively. MBL deficiency in humans is associated with higher susceptibility to viral as well as bacterial infections. A number of single nucleotide polymorphisms (SNP) have been identified in the collagen-like domain of the human MBL gene, of which several are strongly associated with decreased concentrations of MBL in serum. In this study, we have identified a number of SNPs in the porcine MBL-A gene. Sequence comparisons identified a total of 14 SNPs, eight of which were found in exons and six in introns. Four of the eight exon-located SNPs were non-synonymous. Sequence data from several Duroc and Landrace pigs identified four different haplotypes. One haplotype was found in Duroc pigs only, and three haplotypes were found in the Landrace pigs. One of the identified haplotypes was associated with low concentration of MBL-A in serum. The concentration of MBL-A in serum was further assessed in a large number of Duroc and Landrace boars to address its correlation with disease frequency. The MBL-A concentration in Duroc boars showed one single population, whereas Landrace boars showed four distinct populations for MBL-A concentration. The Landrace boars were finally assessed for disease incidence, and the association with the concentration of MBL-A in serum was investigated. No association between MBL and disease incidence was found in this study.     

A two-nucleotide deletion renders the mannose-binding lectin 2 (MBL2) gene nonfunctional in Danish Landrace and Duroc pigs

The mannose-binding lectins (MBLs) are central components of innate immunity, facilitating phagocytosis and inducing the lectin activation pathway of the complement system. Previously, it has been found that certain single-nucleotide polymorphisms (SNPs) in porcine MBL1 and MBL2 (pMBL1, pMBL2) affect mRNA expression, serum concentration, and susceptibility to disease, but the combinatory effect of pMBL1 and pMBL2 genotypes needs further elucidation. In the present study, pMBL1 and pMBL2 alleles, combined pMBL haplotypes, and MBL-A concentration in serum were analyzed in purebred Landrace (N?=?30) and Duroc (N?=?10) pigs. Furthermore, the combined pMBL haplotypes of 89 Piètrain × (Large White × Landrace) crossbred pigs were studied, and the genotypes of 67 crossbreds challenged with Escherichia coli were compared to their individual disease records. In the purebred animals, three non-synonymous SNPs and a two-nucleotide deletion were detected in the coding sequence of pMBL2. The two-nucleotide deletion was present at a frequency of 0.88 in the Landrace pigs and 0.90 in the Duroc pigs, respectively. In the crossbreds, the T allele of the SNP G949T in pMBL1—previously shown to have profound effect on MBL-A concentration even in the heterozygote condition—was detected in 47 % of the animals. Finally, an association was found between low-producing MBL genotypes and low body weight on the day of weaning in the same animals.     

Growth hormone gene polymorphisms and growth performance traits in Duroc, Landrace and Tao-Yuan pigs

This study investigated the restriction fragment length polymorphism (RFLP) of the porcine growth hormone (pGH) gene in Duroc, Landrace, and Tao-Yuan pigs and its effects on growth performance and levels of plasma growth hormone in peripheral circulation. Genomic DNA extracted from 81 Tao-Yuan, 60 Landrace and 48 Duroc pigs were subjected to Southern blot hybridization with a pGH cDNA probe. Polymorphism was detected with the restriction enzymes TaqI and DraI. A comparison of these three breeds showed significant differences in allelic frequencies. Blood samples for radioimmunoassay (RIA) of GH were collected biweekly during the experimental period from pigs 12 to 40 weeks of age. Tao-Yuan pigs showed a mean plasma GH level (2.51 +/- 1.23 ng/mL) that was much lower than that of the Landrace (3.80 +/- 1.52 ng/mL) and Duroc (4.20 +/- 1.03 ng/mL) pigs (P < 0.05). Moreover, the Tao-Yuan pigs also showed poorer growth performance than the Landrace and the Duroc pigs both in the daily weight gain (0.37 +/- 0.06 vs. 0.67 +/- 0.05 and 0.70 +/- 0.05 kg/day, P < 0.01) and feed efficiency (3.12 +/- 0.28 vs. 2.60 +/- 0.14 and 2.52 +/- 0.12, P < 0.05). These results suggest that the growth performance trait in these pigs is highly correlated with their growth hormone genotype.     

Nucleotide variability and haplotype heterogeneity at the porcine fat mass and obesity‐associated (FTO) gene

A large number of studies have confirmed that variants within the fat mass and obesity‐associated (FTO) gene are associated with higher obesity risk in humans. We and others have shown that FTO polymorphisms are associated with fat deposition and related traits in several pig populations, thus confirming the role of this gene in fatness across species. However, some differences observed in different pig populations may be derived, at least in part, from genetic heterogeneity at this locus. Here, we characterise the nucleotide variability and haplotype diversity of the porcine FTO gene in breeds having different predispositions to fat deposition traits. We resequenced 4749 bp of coding and non‐coding regions of the porcine FTO gene in 44 pigs of eight different breeds and identified 27 single nucleotide polymorphisms (SNPs) and four insertions/deletions. A positive Tajima's D‐value (P < 0.10) obtained in Italian Duroc pigs may be compatible with putative balancing selection. From the sequenced pig panel, 20 haplotypes were inferred, some of which clustered according to the breed of origin (Meishan and Italian Duroc). Genetic heterogeneity at this locus could complicate the dissection of the effects of this gene on fat deposition and production traits in pigs. This situation resembles, to some extent, what has been reported in humans, thus making the study of the porcine FTO gene variability especially interesting, as it could be used as a model to understand the complex and elusive role of this gene in human obesity.     

Chaffinch Song Repertoires: Observations,Experiments and a Discussion of their Significance

The relations between innateness and heritability of behaviour, environmental heterogeneity, genetic diversity of populations, and rates of evolution of behaviour are discussed on the basis of a simple quantitative model. An index I of innateness is proposed which can be related to the heritability index h². I and h² are positively related but the degree of correlation depends on the genetic variability of the population, the heterogeneity of the conditioning environment, and the level of spontaneous behavioural variability. The influence of innateness on rates of evolution is moderate. The frequency distributions of I and h² are unimodal, there is no evidence for an innate-acquired dichotomy.     

Single-nucleotide polymorphisms in porcine mannan-binding lectin A

The MBL1 and MBL2 genes encode mannan-binding lectins (MBL) A and C, respectively, that are collagenous lectins (collectins) produced mainly by the liver. Several single-nucleotide polymorphisms (SNPs) in the human MBL2 gene are responsible for various innate immune dysfunctions due to abnormal structure or expression of human MBL-C. The MBL1 gene encodes MBL-A, which has bacteria-binding properties in pigs and rodents but is mutated to a pseudogene in humans and chimpanzees. In these studies, we surveyed both porcine MBL genes for SNPs that might impair disease resistance. Single-strand conformational polymorphism (SSCP) analysis of MBL cDNAs from porcine liver revealed three SNPs within the coding region of MBL1 in various breeds of pigs. One nonsynonymous SNP that substituted cysteine for glycine in the collagen-like domain of pig MBL-A was found by a multiplex PCR test in all European pig breeds examined, with allele frequencies ranging from 1.4 to 46.4%. No SNPs were identified in the coding region of porcine MBL2 but the expression of MBL-C in the liver was widely variable in comparison to the expression of MBL-A, GAPDH, PigMAP, and haptoglobin. These results indicate that some pigs have a miscoding defect in MBL-A and a possible expression defect in MBL-C, which are analogous to coding and promoter polymorphisms that affect human MBL-C.     

母猪繁殖力性状影响因素分析及遗传参数估计

母猪繁殖力是影响种猪场经济效益的重要因素。文章对纯种大白猪、长白猪、杜洛克猪的8491窝产仔记录进行统计分析, 建立固定效应模型对总产仔数、健仔数、初生窝重、弱仔数、死胎数、木乃伊胎数和畸形胎数共7个繁殖性状进行最小二乘分析, 分析胎次、配种季节、品种对母猪繁殖性能的影响, 同时比较了纯繁和杂交的效果。利用动物模型REML(约束最大似然)方法估计繁殖性状的遗传力和遗传相关。结果表明, 胎次、配种季节和品种对总产仔数、健仔数、初生窝重影响极显著(P<0.001), 胎次和品种对弱仔数影响极显著(P<0.001), 但配种季节对弱仔数影响不显著。胎次对死胎数影响显著(P<0.05), 而配种季节和品种对死胎数影响不显著, 胎次、配种季节和品种对木乃伊胎、畸形胎数影响不显著。长白♂×大白♀交配组合具有最高的总产仔数、健仔数和初生窝重。繁殖性状遗传力估计结果显示, 长白猪初生窝重的遗传力最高, 为0.227。其余性状遗传力均在0.2以下, 为低遗传力性状。3个品种母猪的健仔数与初生窝重、总产仔数与健仔数之间的遗传相关达0.96以上。研究结果为降低非传染性因素造成的种母猪产仔数低的问题以及种猪场对母猪繁殖力的选育提高提供了参考数据和理论依据。     

母猪繁殖力性状影响因素分析及遗传参数估计

母猪繁殖力是影响种猪场经济效益的重要因素。文章对纯种大白猪、长白猪、杜洛克猪的8491窝产仔记录进行统计分析,建立固定效应模型对总产仔数、健仔数、初生窝重、弱仔数、死胎数、木乃伊胎数和畸形胎数共7个繁殖性状进行最小二乘分析,分析胎次、配种季节、品种对母猪繁殖性能的影响,同时比较了纯繁和杂交的效果。利用动物模型REML(约束最大似然)方法估计繁殖性状的遗传力和遗传相关。结果表明,胎次、配种季节和品种对总产仔数、健仔数、初生窝重影响极显著(P<0.001),胎次和品种对弱仔数影响极显著(P<0.001),但配种季节对弱仔数影响不显著。胎次对死胎数影响显著(P<0.05),而配种季节和品种对死胎数影响不显著,胎次、配种季节和品种对木乃伊胎、畸形胎数影响不显著。长白♂×大白♀交配组合具有最高的总产仔数、健仔数和初生窝重。繁殖性状遗传力估计结果显示,长白猪初生窝重的遗传力最高,为0.227。其余性状遗传力均在0.2以下,为低遗传力性状。3个品种母猪的健仔数与初生窝重、总产仔数与健仔数之间的遗传相关达0.96以上。研究结果为降低非传染性因素造成的种母猪产仔数低的问题以及种猪场对母猪繁殖力的选育提高提供了参考数据和理论依据。     

The footprint of recent and strong demographic decline in the genomes of Mangalitza pigs

The Mangalitza pig breed has suffered strong population reductions due to competition with more productive cosmopolitan breeds. In the current work, we aimed to investigate the effects of this sustained demographic recession on the genomic diversity of Mangalitza pigs. By using the Porcine Single Nucleotid Polymorphism BeadChip, we have characterized the genome-wide diversity of 350 individuals including 45 Red Mangalitza (number of samples; n=20 from Hungary and n=25 from Romania), 37 Blond Mangalitza, 26 Swallow-belly Mangalitza, 48 Blond Mangalitza × Duroc crossbreds, 5 Bazna swine, 143 pigs from the Hampshire, Duroc, Landrace, Large White and Pietrain breeds and 46 wild boars from Romania (n=18) and Hungary (n=28). Performance of a multidimensional scaling plot showed that Landrace, Large White and Pietrain pigs clustered independently from Mangalitza pigs and Romanian and Hungarian wild boars. The number and total length of ROH (runs of homozygosity), as well as F_ROH coefficients (proportion of the autosomal genome covered ROH) did not show major differences between Mangalitza pigs and other wild and domestic pig populations. However, Romanian and Hungarian Red Mangalitza pigs displayed an increased frequency of very long ROH (>30 Mb) when compared with other porcine breeds. These results indicate that Red Mangalitza pigs underwent recent and strong inbreeding probably as a consequence of severe reductions in census size.     

Identification of endogenous microRNA references in porcine serum for quantitative real-time PCR normalization

MicroRNAs (miRNAs) are evolutionarily conserved small non-coding RNAs that regulate the expression of genes, and they affect important biological and physiological states. Circulating miRNAs in blood are useful markers of metabolism and economic traits. Expression levels of circulating miRNAs have been estimated using quantitative real-time PCR (qPCR). Proper normalization is critical for accurate miRNA expression analysis. However, there is no study which systematically presented endogenous reference genes for evaluating circulating miRNA expression in pigs. In this study, ten porcine miRNAs (let-7a, miR-16, miR-17, miR-23a, miR-26a, miR-93, miR-103, miR-107, miR-127 and miR-191), based on the literature, were chosen as candidate reference miRNAs in serum. We evaluated the expression stability value of these miRNAs in Berkshire, Duroc, Landrace and Yorkshire pigs using geNorm and NormFinder. We determined the optimal combination of reference miRNAs for qPCR experiments: miR-127 and miR-17 in Berkshire pigs; miR-127 and miR-93 in Duroc and Landrace pigs; miR-127 and miR-16 in Yorkshire pigs. miR-127 was the best reference gene in pigs, regardless of the breed. Our study is crucial for the discovery of novel biomarkers in pigs. The reference miRNAs presented in this study could be used as appropriate reference genes for the measurement of circulating miRNA levels in studies of physiological blood metabolites.

     

Evaluation of the porcine melanocortin 4 receptor (MC4R) gene as a positional candidate for a fatness QTL in a cross between Landrace and Hampshire

Melanocortin 4 receptor (MC4R) is expressed in the appetite-regulating areas of the brain where it is central in the regulation of feed intake and energy balance. A mutation in MC4R causing an Asp298Asn substitution has been associated with fatness, high daily gain and feed intake in the pig. In a previously performed genome scan based on a Hampshire x Landrace cross, we detected one quantitative trait loci (QTL) affecting carcass fat/meat ratio and one QTL affecting the biceps femoris muscle, both close to the position of MC4R on porcine chromosome 1. In this study, the two lines were found to be close to fixation for alternative alleles of the Asp298Asn polymorphism. Additional QTL analyses supported our hypothesis of MC4R as a positional candidate gene but only for the fat/meat QTL. The Asp298Asn polymorphism was also evaluated as a selection target for daily gain in a Danish pig breeding population that included four breeds (Hampshire, Duroc, Landrace and Yorkshire). Over a 12-year period (1990-2002), a significant increase in the allele frequency of 298Asn was found in Landrace and Duroc, whereas a non-significant decrease in the 298Asn allele frequency was observed in Yorkshire. The Hampshire breed was fixed for the 298Asn allele in 1990. The high 298Asn allele frequencies in Hampshire, Landrace and Duroc are most likely due to selection for daily gain, whereas selection for daily gain in the Yorkshire breed apparently focuses on other loci.     

Expression profiling analysis for genes related to meat quality and carcass traits during postnatal development of backfat in two pig breeds

The competitive equilibrium of fatty acid biosynthesis and oxidation in vivo determines porcine subcutaneous fat thickness (SFT) and intramuscular fat (IMF) content. Obese and lean-type pig breeds show obvious differences in adipose deposition; however, the molecular mechanism underlying this phenotypic variation remains unclear. We used pathway-focused oligo microarray studies to examine the expression changes of 140 genes associated with meat quality and carcass traits in backfat at five growth stages (1–5 months) of Landrace (a leaner, Western breed) and Taihu pigs (a fatty, indigenous, Chinese breed). Variance analysis (ANOVA) revealed that differences in the expression of 25 genes in Landrace pigs were significant (FDR adjusted permutation, P<0.05) among 5 growth stages. Gene class test (GCT) indicated that a gene-group was very significant between 2 pig breeds across 5 growth stages (P _ErmineJ<0.01), which consisted of 23 genes encoding enzymes and regulatory proteins associated with lipid and steroid metabolism. These findings suggest that the distinct differences in fat deposition ability between Landrace and Taihu pigs may closely correlate with the expression changes of these genes. Clustering analysis revealed a very high level of significance (FDR adjusted, P<0.01) for 2 gene expression patterns in Landrace pigs and a high level of significance (FDR adjusted, P<0.05) for 2 gene expression patterns in Taihu pigs. Also, expression patterns of genes were more diversified in Taihu pigs than those in Landrace pigs, which suggests that the regulatory mechanism of micro-effect polygenes in adipocytes may be more complex in Taihu pigs than in Landrace pigs. Based on a dynamic Bayesian network (DBN) model, gene regulatory networks (GRNs) were reconstructed from time-series data for each pig breed. These two GRNs initially revealed the distinct differences in physiological and biochemical aspects of adipose metabolism between the two pig breeds; from these results, some potential key genes could be identified. Quantitative, real-time RT-PCR (QRT-PCR) was used to verify the microarray data for five modulated genes, and a good correlation between the two measures of expression was observed for both 2 pig breeds at different growth stages (R=0.874±0.071). These results highlight some possible candidate genes for porcine fat characteristics and provide some data on which to base further study of the molecular basis of adipose metabolism.     

Breed difference and regulation of the porcine adipose triglyceride lipase and hormone sensitive lipase by TNFα

Adipose triglyceride lipase (ATGL) and hormone sensitive lipase (HSL) are major novel triglyceride lipases in animals. The aim of this study was to determine if there are differences in the porcine ATGL ( pATGL ) and HSL genes between Jinhua pigs (a fatty breed) and Landrace pigs (a leaner breed). In addition, the effect of TNFα and pATGL-specific siRNA ( pATGL-siRNA ) on the expression of pATGL and HSL in porcine adipocytes was also examined. Compared with Landrace pigs, the body weight ( BW ) of Jinhua pigs was lower ( P <  0.01), while intramuscular fat content (in the longissimus dorsi muscle), as well as the back fat thickness and body fat content were higher ( P <  0.01). The expression of pATGL and HSL mRNA in Jinhua pigs was lower ( P <  0.01) in subcutaneous adipose tissue, and greater ( P <  0.01) in longissimus dorsi muscle compared with Landrace pigs. In vitro treatment of porcine adipocytes with TNFα decreased ( P <  0.01) the glycerol release and the gene expression of pATGL , HSL and PPARγ in porcine adipocytes. Furthermore, transfection with pATGL-siRNA significantly decreased ( P <  0.01) the expression of pATGL , while it had no effect on the expression of HSL . Treatment with 25 ng/ml TNFα in conjunction with pATGL-siRNA significantly decreased ( P <  0.01) the expression of pATGL and HSL in cultured porcine adipocytes. These results provide useful information to further the understanding of the function of pATGL and HSL in porcine lipid metabolism, which should be applicable to the regulation of fat deposition and improvement of meat quality.     

A diet supplemented with l-carnitine improves the sperm quality of Piétrain but not of Duroc and Large White boars when photoperiod and temperature increase

It has been reported that a diet supplemented with l-carnitine can improve sperm quality in some mammalian species. Against this background, the current study seeks to determine the effects of feeding l-carnitine (625 mg·day⁻¹) on boar semen characteristics (ejaculate volume, sperm concentration, sperm viability, acrosome and mitochondrial sheath integrity, sperm motility, sperm morphology, and osmotic resistance of spermatozoa) in three different porcine breeds (Sus domesticus) (Piétrain, Duroc, and Large White) exposed to natural environmental changes in temperature and photoperiod over a 20-wk period (February to July 2007). One hundred twenty boars (40 per breed) were randomly separated into two groups (60 boars each): the first (20 boars per breed) was fed a control diet and the second (also 20 males per breed) the same diet supplemented with l-carnitine (625 mg·day⁻¹). Whereas the l-carnitine supplement did not affect ejaculate volume, concentration, motility, viability, or the osmotic resistance of spermatozoa, it did improve sperm morphology in Piétrain boars by reducing the percentage of immature spermatozoa when the temperature and the photoperiod increased. Conversely, no effect on sperm morphology from supplementing feed with l-carnitine was observed in both Duroc and Large White breeds. We can therefore conclude that the addition of l-carnitine to the diet of males may maintain the level of normal sperm morphology in Piétrain boars when a drop in sperm quality occurs (due to increases in photoperiod and temperature), without affecting the other sperm quality parameters.     

Three types of polymorphisms in exon 14 in porcine Mx1 gene

Much is known about the antiviral activity of Mx proteins in species such as mouse and human. In the mouse, loss of resistibility to influenza virus has been shown to be due to specific polymorphisms in the Mx gene. This gene is therefore an interesting candidate gene for disease resistance in farm animals. The porcine Mx1 gene has already been identified and characterized based on its homology with mouse Mx1; however, until now no evidence of polymorphisms in the porcine gene has been reported. In this study, we have found two new polymorphisms in exon 14 of porcine Mx1 by DNA sequencing and confirmed their presence in different breeds, using polymerase chain reaction (PCR)–restriction fragment length polymorphisms (RFLP) with NarI and NaeI restriction enzymes. On the basis of the deduced amino acid sequence, one allele contains a deletion that may result in a frameshift to yield several amino acid substitutions and extension of the carboxyl terminal region of Mx1 protein. The deletion allele, Mx1 ^c, was found to be segregating in Landrace, Berkshire, Duroc, Hampshire, and Yucatan miniature pig. A second point mutation, Mx1 ^b, was detected in Meishan and two Vietnamese native pig breeds. All other breeds tested were fixed for the Mx1 ^a allele that is identical to the sequence reported previously. It will be interesting to determine if the Mx1 ^c deletion is associated with variation in resistance to the myxovirus family in the pig.     

H2AFZ,RNF4 and NR4A1 loci are associated with boar semen quality by population association studies

Abstract

Spermatogenesis is a complex process regulated by many genes. In this study, H2AFZ, RNF4 and NR4A1 genes were selected as candidate genes for boar semen quality traits based on their functions during spermatogenesis, and the associations of three loci (H2AFZ c.192?+?210–192?+?213delCGAT, RNF4 c.374?+?358 T?>?C and NR4A1 c.956?+?796 A?>?G) with sperm quality traits were analyzed in Duroc (n?=?185), Large White (n?=?87) and Landrace (n?=?49) pig populations. The results showed H2AFZ c.192?+?210–192?+?213delCGAT AA boars produced 1.52% lower abnormal sperm rate (ASR) than AB boars in Landrace pigs (p?<?0.05); RNF4 c.374?+?358?TC boars produced 0.31?×?10⁸/ml higher sperm concentration (SCON) than CC boars (p?<?0.05) in Large White pigs; NR4A1 c.956?+?796 A?>?G was associated with ASR in Duroc and Large White pigs and was associated with sperm motility (MOT) in Large White and Landrace pigs. This study indicated the H2AFZ, RNF4 and NR4A1 loci were the potential molecular markers for improving the semen quality traits in boars.     

Effects of FUT1 gene mutation on resistance to infectious disease

Alpha-(1,2)-fucosyltransferase (FUT1) gene has been identified as a candidate gene for regulating the expression of Escherichia coli F18 receptor gene (ECF18R) which promotes adherence of Enterotoxigenic (ETEC) and Verotoxigenic (VTEC) Escherichia coli (E. coli) via F18 fimbriae. In order to illustrate the polymorphisms of FUT1 and their effects on resistance to natural infection by Porcine Respiratory and Reproductive Symdrome Virus (PRRSV) and Haemophilus parasuis, the distributions of different genotypes and the relative risks of disease incidence in pigs were investigated. A total of 1,041 pigs representing three European breeds (Duroc, Landrace and LargeWhite), five Chinese local breeds (Wild pig, Small MeiShan, QinPing, JinHua, and JianLi) and three commercial populations (LargeWhite?×?JianLi, Duroc?×?Landrace?×?LargeWhite and Duroc?×?wild pig) were selected to analyze the genotype of the FUT1 gene by PCR-RFLP. Only the GG genotype associated with susceptibility to ECF18 bacteria was detected in Chinese local pig breeds and a population of LargeWhite?×?JianLi, while the AA genotype which confers resistance to ECF18 was detected in two European breeds (Duroc and LargeWhite), two populations of Duroc?×?wild pig and Duroc?×?Landrace?×?LargeWhite. Regarding relative risk of incidence, Duroc?×?Landrace?×?LargeWhite with genotypes GG or AG showed greater relative risk (OR?=?2.040, P?=?0.025; OR?=?1.750, P?=?0.081, respectively) than those with genotype AA during natural infection by both PRRSV and Haemophilus parasuis. It can be concluded that the mutation of FUT1 gene might play a role in pig infection by multi-pathogens, and that AA may be a favourable genotype for increasing the resistance to disease.     

Porcine insulin-like growth factor 1 (IGF1) gene polymorphisms are associated with body size variation

Previous studies have confirmed that insulin growth factor-1 (IGF1) plays important roles in growth and body size in humans and animals. However, whether single nucleotide polymorphisms (SNPs) within the IGF1 gene affects body size and growth in pigs has been unclear. We identified IGF1 SNPs among 5 pig breeds (Berkshire, Duroc, Landrace, Yorkshire and Korea Native Pig) and found that the G allele of SNP (c.G189A) was associated with higher body weight and was more predominant in western pig breeds, while the Korean Native Pig is the breed with the highest frequency of the A allele. Four haplotypes (–GA–, –GG–, –AG–, and –AA–) were constructed using the 2 identified SNPs. The GA haplotype was most frequently observed, except in the Berkshire breed. In addition, these SNPs and haplotypes were significantly associated with body size (final weight), average daily gain, and backfat thickness (P < 0.05) in 2 intercrossed F₂ pig populations (KNP × YS F₂ and KNP × LR F₂). Furthermore, the major GA haplotype had a significant additive effect on body size and average daily gain. In conclusion, specific SNPs within the porcine IGF1 gene may contribute to the smaller body size and lower growth rate of Korea Native Pigs.